1. Field of the Invention
The present invention relates to a pinger device and more particularly to a light activated pinger device that is part of a three dimensional homing system.
2. Description of the Prior Art
Underwater target locating is a continuing problem and especially in underwater weapons test ranges. As a rule the general location of an underwater target is known but it is still very difficult to precisely locate even by complex recovery vehicles. Currently underwater recovery vehicles are deployed in the general target location and must attempt to locate the target by underwater television or by homing on a pinger having a constant ping rate. When the pinger is active the target may be located with a directional sonar system. A major problem is encountered when the pinger ceases to operate due to battery drain before the target is located. In this situation visual observation with the assistance of a light source or magnetic detection must be relied upon. Visual observation is severely limited by particulate matter (backscatter) and spectral bandwidth.
The present invention overcomes these problems by providing a light activated acoustic pinger that provides a ping rate that is a function of the distance and angle of the impinging light. This makes possible three dimensional homing by a submersible using only a collimated light source and a directional acoustic receiver to locate the target.